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server.cpp
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server.cpp
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#include "server.h"
#include <iostream>
#include <fstream>
#include <string.h>
#include <stdlib.h>
#include <cstdio>
#include <bits/stdc++.h>
#include <csignal>
#include <sys/poll.h>
#include "tcpFunc.h"
static std::ofstream fout;
static std::string fname;
void signalHandler(int signum){
if (fout.is_open()){
fout.close();
fout.open(fname, std::ofstream::trunc);
fout.write("INTERRUPT", 9);
fout.close();
}
switch (signum){
case SIGQUIT:
//std::cout<< " Interrupt signal SIGQUIT received." <<std::endl;
signum = 0;
break;
case SIGTERM:
//std::cout<< " Interrupt signal SIGTERM received." <<std::endl;
signum = 0;
break;
default:
std::cout<< " Unexpected interrupt signal "<<signum<<" received." <<std::endl;
}
exit(signum);
}
int main(int argvc, char** argv)
{
signal(SIGQUIT, signalHandler);
signal(SIGTERM, signalHandler);
/* Initialize a debugging flag */
bool debug = false;
/* Define port number */
int port;
if (argvc <= 1 ){
port = MYPORT;
if (debug){
std::cout<<"Using default port: 5100"<<std::endl;
}
}
else{
port = atoi(argv[1]);
if (debug){
std::cout<<port<<std::endl;
}
}
/* Define Sockets (one to listen, one to accept the incoming connection) */
int sockfd, new_fd;
/* Define structures to hold addresses */
struct sockaddr_in my_addr;
struct sockaddr_in c_addr;
memset(&my_addr, 0, sizeof(my_addr));
memset(&c_addr, 0, sizeof(c_addr));
unsigned int sin_size;
/* Define a buffer that will store incoming packets */
char buffer[BUFFERSIZE];
memset(buffer,sizeof(buffer),'\0');
/* Initialize the socket, define its address and domain */
if ((sockfd = socket(AF_INET,SOCK_DGRAM,0)) == -1){
perror("ERROR: socket construction failed");
exit(1);
}
my_addr.sin_family = AF_INET;
my_addr.sin_port = htons(port);
my_addr.sin_addr.s_addr = INADDR_ANY;
/* Assign a port to the socket */
if (bind(sockfd, (struct sockaddr*)&my_addr, sizeof(struct sockaddr)) == -1){
perror("ERROR: bind failed");
exit(1);
}
if (debug){
std::cout<<"bind\n";
}
bool connected = false;
struct Header h;
char payload[MSS - sizeof(struct Header)];
socklen_t len = sizeof(struct sockaddr);
/* setup poll events */
struct pollfd ufd[1];
ufd[0].fd = sockfd;
ufd[0].events = POLLIN;
int pret;
int fileID = 0;
uint16_t seqnum = 0;
uint16_t acknum = 0;
while (1){
/* three-way-handshake */
cnct_server(sockfd, buffer, &h, payload, &c_addr, &len);
seqnum = 1;
connected = true;
fname = std::to_string(++fileID) + ".file";
fout.open(fname, std::ios::binary | std::ios::ate | std::ios::trunc);
//fout << "This is a test/n";
//fout.flush();
//std::cout << "Packet Received" << std::endl;
fout.write(payload, h.len);
//std::cout<<std::string(payload)<<std::endl;
struct Header h_ack;
resetFLAG(&(h_ack.flags));
setACK(&(h_ack.flags));
//std::cout<<sizeof(payload)<<' '<<h.seqnum<<std::endl;
acknum = (h.seqnum + h.len) % MAXSEQNUM;
h_ack.acknum = acknum;
h_ack.seqnum = ++seqnum;
writePacket(&h_ack, payload, 0, buffer);
sendto(sockfd, (const char *)buffer, MSS, 0, (const struct sockaddr *)&c_addr, sizeof(c_addr));
logging(SEND, &h_ack, 0, 0);
std::list<Packet> buffered_p;
std::set<uint16_t> buffered_seqnum;
while ( (pret = poll(ufd, 1, RTO)) > 0){
if (recvfrom(sockfd,(char *)buffer, BUFFERSIZE, MSG_WAITALL,
(struct sockaddr*) &c_addr, &len) != -1){
readPacket(&h, payload, PAYLOAD, buffer);
logging(RECV, &h, 0, 0);
if (getFIN(h.flags)){
//wait_cls(2);
cls_resp1(sockfd, buffer, &h, payload, &c_addr, seqnum);
cls_resp2(sockfd, buffer, &h, payload, &c_addr, seqnum);
connected = false;
break;
}
else{
//std::cout << "Packet Received" << std::endl;
char incoming[MSS];
memset(incoming, 0, MSS);
char outgoing[MSS];
memset(outgoing, 0, MSS);
// right packet
if (h.seqnum == acknum){
// Send ack for packet
fout.write(payload, h.len);
acknum = (acknum + h.len) % MAXSEQNUM;
//std::cout<<std::string(payload)<<std::endl;
// Do any of the buffered packets now fall in order?
if (!buffered_p.empty()){
std::list<Packet>::iterator npb = buffered_p.begin();
while(npb != buffered_p.end()){
if (npb->h_seqnum() == acknum){
std::cout << "Erasing "<<npb->h_seqnum()<<std::endl;
fout.write(npb->p_payload(), npb->payload_len());
//std::cout<<std::string(npb->p_payload())<<std::endl;
acknum = (acknum + npb->payload_len()) % MAXSEQNUM;
buffered_seqnum.erase(npb->h_seqnum());
npb = buffered_p.erase(npb);
}
else break;
}
}
Header ack_header;
resetFLAG(&(ack_header.flags));
setACK(&(ack_header.flags));
ack_header.acknum = acknum;
ack_header.seqnum = (++seqnum % MAXSEQNUM);
ack_header.dup = (uint16_t)false;
writePacket(&ack_header, payload, 0, outgoing);
sendto(sockfd, (const char *)outgoing, MSS, 0, (const struct sockaddr *)&c_addr, sizeof(c_addr));
logging(SEND, &ack_header, 0, 0);
}
// out-of-order packet or ( duplicate )
else{
if ((h.seqnum > acknum && (h.seqnum - acknum) <= MAXSEQNUM/2) ||
(h.seqnum < acknum && (acknum - h.seqnum) > MAXSEQNUM/2) ){
if (buffered_seqnum.count(h.seqnum) == 0){
Packet new_p = Packet(&h, payload);
std::cout << "Buffering\n";
std::cout << new_p.h_seqnum() << std::endl;
buffered_seqnum.insert(new_p.h_seqnum());
buffered_p.push_back(new_p);
if (buffered_p.size() > 1){
std::cout << "Sorting \n";
buffered_p.sort(seqnum_comp);
}
}
}
// Send the same ack as before, mark item as a duplicate packet
Header ack_header;
resetFLAG(&(ack_header.flags));
setACK(&(ack_header.flags));
ack_header.acknum = acknum;
ack_header.seqnum= seqnum;
ack_header.dup = (uint16_t)true;
writePacket(&ack_header, payload, 0, outgoing);
sendto(sockfd, (const char *)outgoing, MSS, 0, (const struct sockaddr *)&c_addr, sizeof(c_addr));
logging(SEND, &ack_header, 0, 0);
}
// duplicate packet
}
}
/**********************FILE RECEIVING ENDS HERE**************************/
/************************************************************************/
}
if (pret == -1) perror("polling failed");
else if (pret == 0 & connected == true){
//std::cout<<"Timeout occurred! close connection!"<<std::endl;
if (cls_init(sockfd, buffer, &h, payload, &c_addr, &len, seqnum) == -1)
{
perror("Connection Abort!");
}
}
fout.close();
//std::cout << "Done!" << std::endl;
connected = false;
//std::cout << "Close Connection to Client!" << std::endl;
}
close(sockfd);
return 0;
}